Ever since I was in 4th grade I've always had a regular period. I never had an irregular period.
For some reason this year I'm always delayed by 1 or 2 months or sometimes 3.
I don't know why its like this.
Im in my 2nd year of high school now and this is the first time I've had an irregular period. I had my first period when I was 9 or 10 years old and now I'm 14.
The irregularity of my period only started this year.

There are a lot of things that can cause a late or missed period. It could be that you are exercising more and that is causing you to loose it. It is very common for girls that exercise quite a bit to skip a few months. Also, it can be from weight gain or lose. Now, besides those it could be an issue, such as a possible cyst on an ovary or something of that sort. But most likely it is nothing to worry about. A lot of women's mestrual cycles change. They may go from extrememely regular periods to periods that are far out of the ordinary. Just remember that a women's body is always changing.